Insulating cover



Oct. 4, 1938. R. DEwAR ET AL INSULAT ING COVER Filed May 17, 1954ATTORNEYS.

Patented Oct. 4, 1938 PATENT OFFICE INSULATING COVER Robert Dewar andWilliam T. Sanford,

I-Ioosick Falls, N. Y.

Application May 17,

3 Claims.

This invention relates to insulated covers or caps, and especially toinsulated covers or caps for the distributors or coils which areemployed in the ignition systems of internal combustion engines. Asheretofore constructed, such covers or caps were made from a material,such as Bakelite, having a high insulating value, and they were providedwith a centrally disposed housing member adapted to receive a conductorwhich led from the spark coil to the rotor element of the distributorand with a plurality of peripherally disposed housing members adapted toreceive conductors which led from the contact elements of thedistributor to the spark plugs of the system.

In many instances, however, it is desirable to adjust the intensity ofthe spark toobtain maximum eficiency, and for this reason it is nowcommon practice to employ auxiliary spark intensifying devices betweenthe distributor and the spark plugs. This arrangement however, isunsatisfactory due principally to the fact that the auxiliary unitfrequently becomes disconnected from the system, thereby causing opencircuits.

In accordance with the present invention, however, the above objectionobviated by incorporating adjustable spark intensifying devices in thehousing members of the cap or cover of the distributor.

For a clear understanding of the invention reference may be had to theaccompanying drawing. In the drawing, the invention is shown merely inpreferred form and by way of example but obviously many variations andmodifications may be made therein which will still be comprised within Cits spirit. It is to be understood, therefore, that the invention is notlimited to any specific form or embodiment except in so far as suchlimitations are specified in the appended claims.

Referring to the drawing:

Figure l is an elevational view in section showing one embodiment of theinvention;

Figure 2 is an elevational View in section showing another embodiment ofthe invention; and

Figure 3 is an enlarged view in detail of the adjustable unit employedin the present invention.

Figure 4 is a detail cross section of the intensifying device mounted inthe housing.

As shown, the cover comprises a cup-shaped member I from the centralportion of which a housing member I I opens outwardly and from theperiphery of which a plurality of similar housing members I2 openoutwardly in spaced relation. The number of peripherally disposedhousing members correspond to the number of spark plugs in the system.The cover or cup-shaped 1934, Serial No. 726,060

member I0 and the housing members are desirably moulded as a unit andfrom a substance or compound having a dielectric strength of at least300 Volts per milliampere to prevent failure of the device after it hasbeen in use. A metallic terminal I3 is positioned in the lower end ofeach of the housing members, the lower end of the terminal positioned inthe centrally disposed housing member I I being provided with a carboncontact button I4 through which contact is constantly made with theusual rotor arm (not shown) and the lower ends of the terminalspositioned in the peripherally disposed housing members being extendeddownwardly to form exposed terminals I5 through which contact is madewith the rotor arm as it rotates. The method of establishing electricalcommunication through the distributor cap is well known and detaileddescription thereof is not deemed necessary.

In one embodiment of the invention, as shown in Fig. l, the upper endsor contacting surfaces I6 cf the terminals I3 in the housing members isin contact with the moulding compound or substance but this is desirableonly when the compound or substance has an exceedingly high break downstrength as for example, a break down strength greater than 300 voltsper milliampere since under such conditions there is substantially nocurrent leakage from the terminal through the compound or substance.

In another embodiment of the invention, as Shown in Fig. 2, the centralportion of the upper ends of the terminals I3 in the housing membersform projecting studs I'I so as to provide an air space between theupper ends or contacting faces I6 and the moulding compound orsubstance.

The upper end of each of the housing members is provided with meanswhereby an adjustable spark intensifying device may be assembledtherein, and to this end the upper end of each of the housing members isprovided with screw threads I8. As shown more clearly .in Fig. 3, thespark intensifying device desirably employed comprises a tubular member2B adapted to receive the end of an insulated conductor (not shown) andthe lower end of which is closed to form a contacting face 2|. The outerupper surface of the tubular member is provided with screw threads 22adapted to engage the screw threads I8 in the housing members so thatthe position of the device may be varied in the housing members to varythe spark intensifying properties of the device.

Having thus described our invention, we claim:

l. In combination, an insulating cover comprising a cup-shaped memberhaving a housing mem- 3. In combination, an insulating cover comprisinga cup-shaped member having an internally threaded housing memberextending outwardly therefrom, and a spark intensifying devicepositioned in said housing member, said device comprising a tubularmember having its upper end open and in threaded engagement with saidhousing member and its lower end closed and out of contact with saidhousing member.

ROBERT DEWAR. WILLIAM T. SANFORD.

